This invention relates to polymeric materials. Preferred embodiments relate to thermoplastic composites comprising polymeric materials for use, for example, in the composites industry.
There is a wide range of thermoplastic polymeric material available for use in industry, either alone or as part of composite materials. However, industry is constantly demanding materials with properties which are improved in at least some respect over existing materials.
Polyphenylene sulphide (PPS) is a known polymeric material with a relatively low melting temperature (Tm) of 290° C.; however its glass transition temperature (Tg) is 85° C. to 100° C. which is too low for some applications. On the other hand, polyetheretherketone (PEEK) has a suitable Tg of 143° C. but its Tm of 343° C. is much higher than desirable. Nonetheless, PEEK is the material of choice for many commercial applications because it is highly crystalline and has outstanding chemical resistance properties.
U.S. Pat. No. 4,717,761 (ICI) describes a polymer containing -ether-phenyl-ether-phenyl-carbonyl-phenyl- (i.e. PEEK) and -ether-phenyl-phenyl-ether-phenyl-carbonyl-phenyl- (i.e. PEDEK) repeat units. The copolymer is said to have a low Tm. However, there is no disclosure in the cited reference relating to the level of crystallinity of the copolymer and/or how chemically (e.g. solvent) resistant it may be in use.
It is an object of the present invention to provide a polymeric material per se and a method of making such a polymeric material having a relatively low Tm, a relatively high Tg and a relatively high crystallinity.